The goal of this project is to eliminate and/or reduce substance use and sexual risk acts that transmit HIV and to enhance health care behaviors among HIV + youths. An intensive intervention designed on the AIDS Risk Reduction Model (ARRM) will be evaluated with 540 HIV+ youths aged 14-20 from three AIDS epicenters (Los Angeles [LA], New York [NY], and San Francisco [SF]). Youths receive three 15-20 hour intervention modules (Act Safe, Stay Healthy, and Booster Modules), each delivered during a two month time block. Changes in substance use, sexual risk behaviors, and health practices will be evaluated using a lagged, multiple-baseline design and will be assessed at intake to the agency and every two months over the next 18 months. Half of the youths will be randomly selected to begin receiving the sequence of intervention modules at two months following intake; half will begin receiving the sequenced modules at six months following intake. This lagged design allows us to evaluate the incremental benefits of each intervention module and the cumulative impact of the modules, while complying with ethical standards of care for HIV+ persons. Differential effectiveness will also be examined as a function of three sets of mediating factors: means of acquiring HIV (e.g., homosexual transmission, IV drug use), acquisition of the skills and norms taught in the intervention, and site. Finally, we will examine whether reductions in HIV risk acts are associated with changes in health status (e.g., STDs) and other problem behaviors (e.g., school and conduct problems, suicidality). There are few guidelines on how to adopt the ARRM for HIV+ youths, as the data are very limited. Therefore, prior to initiating the prevention trial, an ethnographic study will document the physical, social, and interpersonal contexts that characterize the lives of HIV+ youths and the process of how HIV+ youths adapt to knowledge of their HIV status.